The present invention relates to an image processing technique for detecting an object included in an image.
Recently, there is a growing need for rich content which reads information on a road sign, a store sign, or the like in an image captured by a smartphone, a drive recorder, or the like and which adds information on the type and position of the road sign or the store sign to map information. For example, an image or a video of a view from a vehicle is captured by a vehicle-mounted terminal such as a smartphone and a drive recorder, and a road accessory such as a sign is detected from the obtained image or from an image included in the obtained video. Subsequently, the vehicle-mounted terminal transmits information on the detected road accessory to a server at a center. The server confirms that the information on the road accessory has been correctly recognized and adds the information to map information.
WO 2006-101012 discloses a technique for detecting a road accessory from an image. With the technique described in WO 2006-101012, a road sign is recognized from an image captured by a camera installed inside a vehicle, information indicated by the recognized road sign is compared with map information and, when there is a difference between the two pieces of information, information of the difference is added to the map information. Road signs include primary signs which indicate a regulation, an instruction, a warning, guidance, and the like and auxiliary signs which supplement the meaning or content of primary signs.